The primary objective of the proposed project is to investigate the perinatal effects of human support during labor in a United States population. The prospective, randomizated application of continuous support (provided by research companions) and natural variations in family support will be examined for their effects on the course of labor and the incidence of perinatal problems in 1000 primigravidous mothers and their newborns. The experimental procedures and methods of data collection have been refined and thoroughly tested in a 4-month pilot study. The specific aims of the project are to determine the effects of support on (1) the length of labor, when not shortened by pitocin agumentation or terminated by cesarean section, (2) the incidence of obstetric interventions during labor and delivery, such as analgesia, pitocin augmentation, and forceps, (3) the incidence of cesarean section, and (4) the incidence of perinatal problems in the fetus and neonate, such as abnormal fetal heart rate patterns, asphyxia, passage of meconium, neonatal depression, and respiratory distress. Two preliminary studies conducted in Guatemala revealed substantial effects of support in each of these areas, but it is not known to what extent the findings can be generalized to a United States population. Furthermore, the Guatemala studies did not consider the effect of family support and provided no clue as to the mechanism by which support influences perinatal outcome. Therefore, a secondary objective of the proposed project is to examine the extent to which the relationship between support and perinatal outcome can be explained by variations in maternal catecholamine levels in a subsample of 60 mothers. The results of the proposed project will contribute to the knowledge base that is necessary to make rational decisions concerning changes aimed at improving the care of mothers and infants in the perinatal period. If the results are similar to those in Guatemala, there will be convincing evidence for the provision of low-cost support in United States hospitals, with major financial and individual benefits for mothers and newborns.